Replacing strings

Problem

You want to replace one string by another in one or many files.

Solution

You can use sed to do various string manipulation tasks

To replace old-word by new-word

    sed -i 's/old-word/new-word/g' *.txt

    #in mac
    sed -i '' 's/old-word/new-word/g' *.txt
    sed 's/old-word/new-word/g' *.txt

Some times the words contain single quotes, in these cases, we have to escape them like so

    sed 's/old-word/new'\''word/g' *.txt

If you want sed to read from standard input, you have to use -e option

    echo "hello world" | sed -e 's/hello/hi/g'
    > hi world